Integrated Mechanical Model of [r]-[l] and [b]-[m]-[w] Producing Consonant Cluster [br]

We have developed two types of mechanical models of the human vocal tract. The first model was designed for the retroflex approximant [r] and the alveolar lateral approximant [l]. It consisted of the main vocal tract and a flapping tongue, where the front half of the tongue can be rotated against the palate. When the tongue is short and rotated approximately 90 degrees, the retroflex approximant [r] is produced. The second model was designed for [b], [m], and [w]. Besides the main vocal tract, this model contains a movable lower lip for lip closure and a nasal cavity with a controllable velopharyngeal port. In the present study, we joined these two mechanical models to form a new model containing the main vocal tract, the flapping tongue, the movable lower lip, and the nasal cavity with the controllable velopharyngeal port. This integrated model now makes it possible to produce consonant sequences. Therefore, we examined the sequence [br], in particular, adjusting the timing of the lip and lingual gestures to produce the best sound. Because the gestures are visually observable from the outside of this model, the timing of the gestures were examined with the use of a high-speed video camera.